POST UTME ELIZADE UNIVERSITY 2021 Chemistry | Objective
Practice these randomly selected questions to test your readiness.
Question 1
A 2.5 M solution of NaOH is mixed with a 1.5 M solution of HCl. Calculate the pH of the resulting solution.
Question 2
The element with the symbol 'Ag' is a(n) _______________ metal.
Question 3
The compound CH3COOH is an example of a(n) _______________.
Question 4
A polymer has a molecular weight of 100,000 g/mol. If 1 g of the polymer is dissolved in 100 mL of water, what is the concentration of the solution in g/L?
Question 5
At 273 K, the root mean square speed of a gas is 200 m/s. What is the temperature at which the root mean square speed is 400 m/s?
Question 6
The reaction: 2NO(g) + O2(g) → 2NO2(g) has a rate cons\tant of 0.05 s-1 at 298 K. What is the rate of reaction if the initial concentrations of NO and O2 are 0.1 M and 0.05 M, respectively?
Question 7
In a study on the environmental impact of pesticides, a researcher finds that the concentration of a particular pesticide in a water sample follows the first-order kinetics equation: ln\( [A]t/[A]0 \) = -kt. If the initial concentration of the pesticide is 10 mg/L, and after 5 days, the concentration is 5 mg/L, what is the rate cons\tant (k) of the reaction?
Question 8
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. The s\tandard enthalpy of formation of H2O(l) is -285.8 kJ/mol. Calculate the s\tandard enthalpy of formation of CH4(g) u\sing Hess's law.
Question 9
The diagram below shows a simple black and white chemistry apparatus setup for a titration reaction. Identify the part labeled B.
Question 10
A gas at 300 K and 1 atm is compressed to 2 atm. Calculate the new volume of the gas, assuming ideal behavior.
Question 11
A sample of sulfur dioxide gas (SO2) is collected over water at a temperature of 25°C and a pressure of 1 atm. If the volume of the gas is 2.5 L, and the partial pressure of water vapor is 0.02 atm, what is the mole \fraction of SO2 in the gas mixture?
Question 12
A metal with a density of 8.5 g/cm^3 has a mass of 25 g. Calculate the volume of the metal.
Question 13
A mixture of 2.0 g of sodium carbonate (Na2CO3) and 1.0 g of sodium chloride (NaCl) is dissolved in 100 mL of water. If the density of the solution is 1.05 g/mL, what is the molality of the solution?
Question 14
The atomic number of an element is 12. What is the number of electrons in a neutral atom of this element?
Question 15
The element with the symbol 'O' is a(n) _______________ nonmetal.
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